var user={name:"dingding",age:20,qq:"2594820686"};
//字符串
console.log("username:%s",user.name);
//整数
console.log("age:%d",user.age);
//json
console.log("user:%j",user);

function longTask(){
    for(var i=0;i<10000;i++){
        for(var j=0;j<10000;j++){
            var n=i*j;
        }
    }
}
console.time("test");
longTask();
console.timeEnd("test");
console.timeStamp();//时间戳